FLIGHT, 18 March 1960 367
Aero Engines 1960
IN our 1960 review of the world's aero engine*—written by the
Technical Editor—we have been deliberately partial. Engines
for missiles and space vehicles are ignored, and small or relatively
unimportant aircraft powerplants are dealt with only briefly.
This has been done in order that closer than usual attention
may be paid to engines of great importance on either technfcal
or commercial grounds. Few powerplants are of such interest—on
both counts—as are the new families of what, for want of a
universally accepted word, we may call fan engines. Sir Frank
Whittle drew them first, Metropolltan-Vickers made them first and
Rolls-Royce put them Into service first (with the engine whose
business end appears behind these words). Cunning engineers In
America added fans to existing turbojets, and claimed
superiority for their higher by-pass ratios. Now the hubbub is
dying away, and the backroom nnen are generally agreed on
what high-subsonic engines should be like. But—like the sponsors
of detergents—they will still call them by different names.
GREAT BRITAIN
ALVIS Alms Ltd, Coventry. Notwith-
standing unofficial rumours of the company's
interest in small gas-turbines—linked with the
name oF Rolls-Royce—Alvis have made no
announcement of such activities, and in the
aero-engine field continue to concentrate upon
their established reciprocating engines.
Leonides The two principal variants of
this highly developed radial are the series 514,
in wide service with the Scottish Aviation
Twin Pioneer and Hunting President, and the
series 531, the first production variant of the
uprated long-stroke version.
Still in production, the 514 differs from the
later engines in having a stroke of 4.41in and
in certain other minor respects. Maximum
rated power is 560 b.h.p. at 3,000 r.p.m. with
81b/sq in boost; the engine is designed to
operate on 100-octane fuel, but can accept
lower grades after minor modifications. It is
basically an improved Leonides 503 and has
been subjected to some 6,5OOhr bench running
and 50,000hr in flight. Full ARB and FAA
approval has been obtained and the present
overhaul life is 1,000 to l,200hr.
In addition to having an increased stroke,
the Leonides 531 incorporates longer pistons
and a generally stronger carcase. Equipment
includes a Hobson fuel-injection system and
either electric or cartridge starting. This mark
of Leonides has run some 2,000hr on the bench
and l,200hr in flight, and has ARB approval
with an overhaul life of 400 to 600hr.
Leoaidcs Major This powerplant employs
two rows each of seven short-stroke Leonides
cylinders, giving an overall swept volume of
1,118 cu in. The most important variant is the
series 755, for the latest piston-engined West-
land Whirlwinds. In these it is installed with
the crankshaft at 35° from the horizonal, the
drive being transmitted direct to the rotor hub
by way of a dutch and cooling fan. Weighing
1,1101b, the 755 has a Ihr rating of 795 b.h.p.
at 2,900 r.p.m. with 6.51b/sq in boost at a
height of 3,250ft Some 7,000bx bench run-
ning and many thousands of hours in flight
have been logged by 755s; full ARB approval
has been obtained, with an overhaul life from
250 to 400hr.
BLACKBURN Blackburn Engines
Lid, Division of tht Hauthtr Siddeley Group,
Brough, East Yorks. In October 1952 the
former Cirrus Engine Dmtioa acquired a
licence for Turbomeca gas turbines. Many of
these engines were then in an early state of
development, and they were redesigned at
Brough and turned into fully equipped aircraft
powerplants. The most important from the
viewpoint of aircraft propulsion are the free-
turbine engines described below. In addition
Blackburn have made a number of Palouste air-
compressors for helicopters and are in bulk
production with this engine for starter trolleys
and pods for the Royal Navy and RAF. The
single-shaft Artouste drives a large English
Electric alternator and other equipment as the
AAPP for the Victor, and Blackburn expect
future prospects for such units to be good.
Regarding piston engines, an order for a further
batch of Bombardier 208s was placed recently
and Blackburn also overhaul all their piston
engines and the many Psloustes now in service.
A.129 Although incorporating many com-
ponents of the Turmo and Artouste, the A.129
gives twice the power with improved efficiency,
chiefly by the addition of a two-stage axial
compressor and of a second stage to the com-
pressor turbine. The accessories are mounted
behind the annular intake and other features in-
clude variable inlet fPilitGii£!tflHS^ttBdLAa$IBtNYWf
an integral oil tank can tie provided around the
intake.
The gas-producer portion was run as a
turbojet in JijjpT958, and the complete engine
was bpgeh-tested at 840 s.h.p. in August of that
ye»#;ttTJevelopment has since been encourag-
ing, and a simulated type-test has already been
run. An M.o.A. development contract has
been placed for A. 129s for the Saunders-Roe
Wasp, and much flying has been logged in
these aircraft. Blackburn are discussing other
applications, and selling price should be under
£10,000.
Turmo The Saunders-Roe P.531 Mk 0,
a batch of which are being evaluated by the
Royal Navy, are powered by a Turmo rated at
400 s.h.p. for a weight of 2751b. These engines
have intake and exhaust trunks on either side,
and a rear drive.
BRISTOL SIDDELEY Bristol Siddeley
Engines Ltd, Mercury House, 19S Knights-
bridge, London SW1. Since Armstrong
Siddeley Motors and Bristol Aero-Engines
merged to form Bristol Siddeley Engines in
The engine drawings on the following 20 pages are superimposed on black panels representing a width of 5ft